OTHER THEORIES OF SPECIES-FORMING. 293 



usually affects the upper parts of both ears, and may then gradually 

 extend downward until nearly the whole ear is involved. 'As re- 

 gards the progeny of animals thus affected in some cases, but by 

 no means in all, a similarly morbid state of the ears may arise 

 apparently at any time in the life history of the individual. But 

 I have observed that in cases where two or more individuals of the 

 same litter develop this diseased condition, they usually do so at 

 about the same time, even though this may be months after birth, 

 and therefore after the animals are fully grown.' Moreover, the 

 morbid process never extends so far in the young as it does in the 

 parents, and 'it almost always affects the middle third of the ear/ 

 Several of the progeny from this first generation, which had appa- 

 rently inherited the disease, but had not themselves been directly 

 operated upon, showed a portion of the ear consumed apparently 

 by the same disease. Romanes then gives the following signifi- 

 cant analysis of this result. Since a different part of the ear 

 of the progeny is affected, and also a Very much less quantity 

 thereof, it might seem that the result was due either to a mere 

 coincidence, or to the transmission of microbes. But he goes on 

 to say, that he fairly well excluded both of these possibilities, for, 

 in the first place, he has never observed 'the very peculiar process 

 in the ears, or in any other parts of guinea-pigs which have neither 

 themselves had the restiform bodies injured, nor been born of 

 parents thus mutilated.' In regard to microbes, Romanes tried to 

 infect the ears of normal guinea-pigs by first scarifying these parts, 

 and then rubbing them with the diseased surfaces of the ears of 

 affected guinea-pigs. In not a single case was the disease produced. 



"Romanes concludes that these 'results in large measure corrobo- 

 rate the statements of Brown-Sequard; and it is only fair to add 

 that he told me they were the results which he had himself obtained 

 most frequently, but that he had also met with many cases where the 

 diseased condition of the ears in parents affected the same parts in 

 their progeny and also occurred in more equal degrees.' 



"We come now to the remarkable conclusion given in Brown- 

 Sequard' s 7th statement, in regard to the absence of toes in animals 

 whose parents had eaten off their own hind toes and even parts 

 of their legs. Romanes got neuroses in the animals operated upon, 

 and found that the toes might be eaten off; but none of the young 

 showed any defect in these parts. Furthermore, Romanes repeated 

 the same operation upon the descendants through six successive 

 generations, so as to produce, if possible, a cumulative effect, but no 

 inheritance of the mutilation was observed. 'On the other hand, 

 Brown-Sequard informed me that he had observed this inherited 

 absence of toes only in about one or two per cent, of cases.' It is 



